Amorphous Water-Soluble Calcium Citrate Salts and Method of Making and Using Same

ABSTRACT

Amorphous water-soluble calcium citrate salts having a mole ratio of calcium to citrate of less than 2.5:2, and powdered beverage mixes and liquid compositions fortified with these amorphous water-soluble calcium citrate salts as a calcium source, are provided. Liquid compositions fortified with calcium citrate according to this invention have superior dispersability, solubility, appearance, and storage stability. These liquid compositions are prepared by new methods that provide and preserve a stable amorphous character in the dry powdered product salts. The present invention also is directed to a method of administering such calcium citrate-fortified liquid compositions to increase the dietary calcium intake in individuals.

FIELD OF THE INVENTION

The present invention generally relates to amorphous water-solublecalcium citrate salts and foods and beverages (including powdered drinkmixes and liquid compositions) fortified with such calcium citratesalts.

BACKGROUND OF THE INVENTION

The mineral calcium forms an important part of proper nutrition. Calciumis essential for bone and tooth formation. Approximately 99 percent ofthe calcium in the body is stored in bones and teeth, while theremaining 1 percent is present in the blood and soft tissues ascirculating calcium (generally in the form of Ca⁺² ions). Thecirculating calcium is essential for proper muscular contraction, bloodclotting, and nerve transmission functions. In addition to theirstructural role, bones provide an emergency supply of circulatingcalcium.

Osteoporosis is a widespread problem, afflicting approximately twentymillion women and five million men in the United States to some degree.Post-menopausal women typically lose about 0.7 to 2 percent of theirbone mass per year, while men lose about 0.5 to 0.7 percent.Consequently, between the ages of 45 and 70, women and men can loseabout 30 and 15 percent, respectively, of their skeletal mass. In theUnited States more than one million bone fractures occur annually inwomen 45 years or older; in about 70 percent of these cases,osteoporosis plays a significant role. There are approximately 190,000hip fractures annually in the United States; hip fractures are thesecond leading cause of death in people 47-74 years of age. More recentstudies have suggested that reduced calcium intake in children mayresult in increased risk for osteoporosis later in life.

Dietary calcium supplementation and fortification is recognized in thehealth field as a convenient and safe approach for addressing calciumdeficits. The Recommended Dietary Allowances (RDA's) for calcium by theNational Academy of Sciences are 1,200 mg/day for adults 51+ years old;1,000 mg/day for adults 19-50 years old; 1,300 mg/day for children 9-18years old; 800 mg/day for children 4-8 years old; and 500 mg/daychildren 1-3 years old. The US Daily Value (DV) for calcium is 1000mg/day for all individuals; this reference value is typically used toestablish nutritional calcium levels in food products. The Food and DrugAdministration (FDA) permits foods and beverages containing at least 100mg calcium per serving to be labeled as a “good source of calcium”;those containing at least 200 mg calcium per serving may be labeled asan “excellent source of calcium.”

However, many conventional dietary sources of calcium contain lower thandesired levels of calcium. Simply increasing the amount of calcium usingconventional fortification techniques to provide more nutritionallydesirable levels often unfavorably impacts the food product's pH,flavor, texture, appearance, and/or cost. Another problem is that manyconventional dietary sources of calcium have low solubility ordispersability in water and tend to precipitate in aqueous solutions,forming turbid fluids and/or sediments which can impart undesirablechalky or gritty attributes in beverages. Such quality defects candecrease consumer acceptance and limit consumption, thereby reducing thenutritional benefits afforded by such calcium-containing products.

Among the conventional calcium citrate compounds most commonly used infoods, crystalline tricalcium dicitrate (i.e., tricalcium citrate or“TCC”; calcium:citrate mole ratio of 3:2) has limited utility inbeverage applications since it is virtually insoluble in water. The TCCingredient most commonly used in food fortification is crystalline TCCtetrahydrate. Although this material contains a high level of calcium(about 21 percent), it only provides about 6 mg of soluble calcium perfluid ounce of water at room temperature due to its low solubility(i.e., less than 0.1 percent in water at room temperature); this levelof fortification would provide only about 5 percent of the U.S. DV forcalcium in soluble form; simply attempting to add greater amounts towater would result in immediate precipitation. Other sparingly solublecalcium citrates like crystalline monocalcium dicitrate (i.e.,monocalcium citrate or “MCC”; calcium:citrate mole ratio of 1:2) andcrystalline dicalcium dicitrate (i.e., dicalcium citrate or “DCC”;calcium:citrate mole ratio of 2:2) also have limited utility due to slowdissolution, incomplete dispersion, or undesirable sedimentation.

U.S. Pat. No. 4,851,221 describes a dry powdered premix of citric acidand calcium hydroxide in a mole ratio of between about 0.6 to about 1.5,which is combined directly with a potable liquid to make a solutionreported to have enhanced calcium bioavailability. The premix, afterbeing dissolved in water, is reported to form calcium citrateprecipitates within several hours after dissolution in water unless thepH is below about 3.5. The relatively low pH value required to avoidprecipitation of the calcium citrate is a significant limitation on theusefulness of the premixes described therein. Moreover, calciumhydroxide is strongly alkaline and can cause degradation and/ordiscoloration of many commonly used food ingredients (especially ifthere is exposure to moisture during storage), thereby leading to a poorquality product with a reduced shelf life.

U.S. Patent Application 2002/0122866 describes a method and apparatusfor producing a calcium fortified liquid beverage by forming a solutioncontaining a soluble calcium salt of an organic acid and immediatelyblending with a liquid beverage in a continuous manner to avoidformation and precipitation of insoluble salts. No soluble calciumcitrate or other salts in dried form were disclosed.

Calcium salts of organic acids have been used in food processing. U.S.Pat. No. 5,208,372 describes a solid calcium citrate anti-caking agentthat is a water insoluble crystalline calcium citrate salt at ambienttemperature having a calcium:citrate ratio of 2.5:2 to 2.95:2, and whichalso is said to be useful in powdered soft drinks sweetened withfructose. U.S. Pat. No. 5,219,602 describes an aqueous dispersioncontaining the crystalline calcium citrate salt having a calcium:citrateratio of 2.5:2 to 2.95:2, which can be used to opacify and whiten foodcompositions. The insoluble crystalline calcium citrate salts describedin these patents are formed by combining a calcium compound with citricacid in water and allowing adequate time for the reaction product tosolidify before drying.

U.S. Pat. No. 6,235,322 describes highly soluble and stable mineralsupplements containing calcium and magnesium. In particular, afiber-free calcium/magnesium material is provided by solubilizing acalcium/magnesium mixture in an aqueous acid solution and drying thereaction product. The use of magnesium is reported to increase calciumsolubility and help to provide adequate time for solutions to solidifyprior to freeze drying or tray drying. Numerous specific examples ofsalts other than calcium citrates are provided.

As can be appreciated, there remains a need for approaches forfortifying instant and ready-to-drink (RTD) beverages with safe,convenient, and compatible forms of nutritional high-calcium salts thatcan provide calcium at high dietary levels and which provide improvedsolubility and increased shelf life stability. The present inventionfulfills these, as well as other needs and objectives, as will beapparent from the following description of embodiments of the presentinvention.

SUMMARY OF THE INVENTION

This invention provides new amorphous water-soluble calcium citratesalts having a mole ratio of calcium to citrate of less than 2.5:2.These new amorphous calcium citrate salts should have enhanced stabilityand bioavailability relative to currently available calcium salts. Thesenew amorphous water-soluble calcium citrate salts, which can be producedwith high calcium levels, have enhanced dispersability, solubility, andstability in water relative to currently available calcium citrate saltsand other commercially available high calcium salts (e.g., calciumfumarate, calcium carbonate, calcium phosphate, and the like). Thepresent water-soluble amorphous calcium citrate salts are also useful ascalcium fortifying agents that are rapidly and wholly dissolved inaqueous compositions. These amorphous water-soluble calcium citratesalts are especially useful when incorporated into ready-to-drink(“RTD”) liquid compositions or powdered beverage mixes which may bereconstituted in water to provide beverages. Indeed, it has beensurprisingly found that these amorphous water-soluble calcium citratesalts can significantly improve the appearance and extend the shelf lifeof liquid compositions such as acidified RTD beverages as compared tothe use of conventional calcium citrate salts.

For purposes herein, “amorphous” means noncrystalline (i.e., thecompound lacks a distinct crystalline structure). Crystalline substancesoften contain relatively small amounts of non-crystalline matter andsuch structural defects do not detract from classification of thesesubstances as crystalline since the physical properties of thesesubstances are determined by their predominantly crystalline nature.Similarly, amorphous substances often contain small amounts ofcrystalline matter that do not significantly detract from their uniquephysical properties. The amorphous calcium citrate salts of theinvention were produced according to new methods disclosed herein forthe express purpose of preventing crystallization to the greatest extentpractically possible while enabling production of these salts on a largescale using modified food processing techniques and common dryingequipment. However, it should be understood that amorphous calciumcitrate salts prepared according to embodiments of the invention mightcontain small amounts of microcrystalline matter that can be toleratedwithout meaningful effect on the gross physical characteristics of theseunique ingredients or on the enhanced performance benefits theseingredients provide in food and beverage fortification. For purposes ofthis invention, a calcium citrate salt will be considered amorphous ifit contains only a small amount of microcrystalline matter; typically,the amorphous calcium citrate salts of this invention contain less thanabout 10 percent, preferably less than about 5 percent, and morepreferably less than about 1 percent, of crystalline material.

The amorphous water-soluble calcium citrate salts of embodiments of thisinvention rapidly dissolve in water to form clear haze-free,sediment-free liquid compositions which can provide high levels ofcalcium. For purposes of this invention, the calcium citrate salts ofthis invention are considered “water soluble” if, when dissolved inwater to provide about 10 mg calcium per fluid ounce, they do not form avisible haze or sediment for at least about 2 days at ambienttemperatures. Liquid compositions (e.g., RTD beverages) formulated withthese salts are stable and have long shelf lives (generally greater thanabout 6 months when properly packaged); for purposes of this invention,shelf life refers to the period of time during which no visibleprecipitation or sedimentation occurs when stored at ambienttemperatures. The new amorphous water-soluble calcium citrate saltremains in solution for long periods of time, thereby providing a goodsource of dietary calcium.

In one embodiment of the present invention, amorphous water-solublecalcium citrate salts are provided which are represented by thefollowing formulas:

wherein “n” is a value of less than 2.5, preferably less than about2.25, and more preferably ranging from about 1 to about 2. The “C₆H₅O₇”portion of the above formula represents a citrate moiety.

The calcium content of these amorphous water-soluble calcium citratesalts can easily be adjusted to obtain calcium:citrate mole ratios ofless than 2.5:2 to fit a wide range of nutritional liquid and foodapplications. Especially preferred compositions that can be fortifiedwith the unique amorphous water-soluble calcium citrate salts of thisinvention include instant beverage mixtures and RTD beverages such as,but not limited to, fruit drinks, health drinks, soft drinks, andpharmaceutical potions. However, the low-to-moderate pH andslight-to-moderate acid flavor of the present amorphous water-solublecalcium citrate salts in solution make them particularly suitable foruse in acidified or naturally acidic instant or RTD beverages. Theamorphous water-soluble calcium citrate salts can be used alone or incombination with other calcium sources to provide sufficient amounts ofdietary calcium. Preferably, the amorphous water-soluble calcium citratesalts are used as the sole source of calcium. In addition, otheressential minerals or elements (e.g., iron, zinc, potassium, and thelike) can be added to enhance nutrition, modify physical-chemicalproperties, or improve handling. Such other essential minerals orelements can be added to the amorphous water-soluble calcium citratesalts themselves or incorporated into the amorphous water-solublecalcium citrate salts during preparation thereof.

In another aspect of the invention, these new calcium salts are preparedby a unique method that provides and preserves amorphous character inthe dry powdered salt products, thereby providing a more rapidly andcompletely water-soluble, and water-stable (i.e., no visibleprecipitation or sedimentation) material. In one embodiment, thepreparation method comprises neutralizing a concentrated solution ofcitric acid (generally at least about 1 percent citric acid andpreferably about 20 to about 30 percent citric acid) with a slurry ofcalcium oxide or calcium hydroxide in water in the appropriate moleratio and at a temperature of less than about 30° C. and then rapidlydrying the reaction mixture. The drying must occur shortly after thereaction mixture containing the calcium citrate reaction product isformed in order to prevent transformation of the amorphous calciumcitrate product into less stable, water-insoluble crystalline forms ofthe salt. How quickly the drying should take place depends, at least inpart, on the temperature. Generally and under refrigeration conditions,such rapid drying should be carried out within about 30 minutes, andpreferably within about 15 minutes, of the reaction mixture formation.Generally and under ambient conditions, such rapid drying should becarried out within about 5 minutes, and preferably within about 2minutes, of the reaction mixture formation. Alternatively, the reactionmixture can be quickly frozen (generally within about 5 minutes,preferably within about 2 minutes, and more preferably with about 1minute of the reaction mixture formation) for later drying; once frozen,the reaction mixture should be dried under conditions which prevent orminimize thawing. In one embodiment, a rapid drying procedure comprisingfreeze drying or spray drying is used. Where freeze drying is used, thefrozen solid piece or pieces obtained are comminuted into a powder formafter freeze drying. Where spray drying is used, the calcium and citricacid reactants preferably are chilled at the time of their admixture andup until drying.

In one embodiment of the invention, a calcium-fortified aqueouscomposition is provided containing greater than about 12.5 mg calciumfrom the amorphous calcium citrate salt per fluid ounce serving, andgreater than about 100 mg calcium per eight fluid ounce (about 240 ml)drink. Thus, a single eight-ounce serving of such a calcium-fortifiedbeverage would provide greater than about 10 percent of the recommendedU.S. DV for calcium. In another embodiment, a calcium-fortified aqueouscomposition is provided containing about 30 to about 50 mg calcium fromthe amorphous calcium citrate salt per fluid ounce serving, and about320 to about 400 mg calcium per eight fluid ounce (about 240 ml) drink.Thus, a single eight-ounce serving of such a calcium-fortified beveragewould provide about 25 to about 40 percent of the recommended U.S. DVfor calcium. In still another embodiment, a calcium-fortified aqueouscomposition is provided containing sufficient calcium from the amorphouscalcium citrate salt per eight fluid ounce (about 240 ml) drink toprovide at least about 50 percent of the DV level, and preferably atleast about 100 percent of the DV level.

The amorphous water-soluble calcium citrate salts of this invention,even when used to provide high levels of calcium fortification, aretypically present in instant beverage mixes and liquid food compositionsat much lower concentration than the reaction mixtures from which theywere formed. The comparatively dilute solutions that typify nutritionalproduct applications greatly reduce and often eliminate the tendency ofthese amorphous salts to be transformed to an insoluble crystallinematerial. In addition, the preferred use of these ingredients inacidified beverage products containing citric acid or other food acidstypically further reduces the tendency of the dissolved amorphous saltsto be transformed to an insoluble crystalline material. By comparison,the citric acid or other food acids present in such preferredapplications is typically not able to dissolve a significant amount ofinsoluble material produced by crystalline commercial calcium citratesalts when they are used at levels needed to provide effectivefortification.

In another embodiment of the present invention, a method is provided tosupplement dietary calcium intake in individuals by administering aneffective amount of the amorphous calcium citrate salts of thisinvention, preferably in the form of a calcium-fortified liquidcomposition.

As will be appreciated from the descriptions herein, a stable, rapidlydissolving calcium citrate powder with high calcium content is providedwhich is useful in calcium fortified beverages and foods, includinggelled or structured foods and beverages, to provide a highly functionaland soluble dietary calcium source. The amorphous water-soluble calciumcitrate fortified beverage drinks of this invention have excellentstorage stability without calcium citrate sedimentation or turbidity.They also are highly palatable and are essentially free of unacceptableoff-tastes or off-flavors, even at relatively high addition levels.

DETAILED DESCRIPTION

The present invention generally relates to the production of new calciumcitrate salts under controlled conditions effective to provide anamorphous water-soluble salt product that dissolves rapidly in aqueousfluids to form clear, haze-free and sediment-free drinks and beverages.These new calcium citrate salts are highly useful calcium fortifyingagents for beverages and foods. Unlike crystalline calcium citratesalts, such as tricalcium citrate salts, RTD beverages and reconstitutedpowdered beverages containing the amorphous calcium citrate salts of thepresent invention exhibit a clear, non-turbid appearance and remainsediment-free throughout their shelf life. Consequently, amorphouswater-soluble calcium citrate compounds of the present invention providea readily available nutritional calcium source which can be used in awide variety of food products. The new amorphous water-soluble calciumcitrate salts described in embodiments herein also are compatible withmany common and otherwise useful additives used in food and beverageformulations. For instance, beverage formulations can include flavoringagents, sweeteners, acidulants, stabilizers, and so forth, withoutinducing haze formation from solid particle suspension, orsedimentation, of the calcium citrate salts.

In one aspect, the present invention relates to amorphous water-solublecalcium citrate salts of the formulas:

wherein “n” is a value of less than 2.5, preferably less than about2.25, and more preferably about 1 to about 2. The “C₆H₅O₇” portion ofthe formula represents a citrate moiety.

The amorphous water-soluble calcium citrate salts of this invention areprepared by reacting a calcium compound with citric acid in an aqueousmedium to produce calcium citrate having a calcium to citrate mole ratioof less than 2.5:2. The resulting reaction mixture is then quickly dried(or quickly frozen for drying at a later time) in order to separate andisolate amorphous calcium citrate as a dry powder. It is important thatthe amorphous water-soluble calcium citrate reaction salt is recoveredfrom the aqueous reaction mixture as a dry amorphous material before itcan be transformed into insoluble crystalline tricalcium citrate (TCC)or other water-insoluble calcium citrate salts. As shown in the examplesbelow, both the condition of providing a calcium:citrate mole ratio ofless than 2.5:2, and the condition of drying the reaction mixture soonenough after the salt-producing reaction, as detailed herein, to avoidreaction product transformation into water-insoluble calcium citratesalts, are important to ensure that the solid calcium citrate reactionproduct is recovered in an amorphous state. Preferably rapid dryingtechniques are also used to minimize the opportunity for crystallizationof the reaction product during the drying operation. Suitable rapiddrying techniques include, for example, freeze drying and spray drying.

Powdered forms of the amorphous water-soluble calcium citrate saltsprepared having the mole ratio values prescribed herein are quickly andcompletely dissolve in water. Consequently, clear, haze-free,sediment-free aqueous compositions can be prepared with them. Bycontrast, calcium citrate salts that are either crystalline or have acalcium/citrate mole ratio of greater than 2.5:2 are observed to benoticeably water-insoluble, and liquid compositions formulated with theminclude undesirable solid (undissolved) calcium citrate particulatesuspensions (yielding a hazy appearance and/or gritty texture) orsediments. Such undissolved forms of calcium, in addition to beingvisually and/or organoleptically undesirable, can reduce the amount ofdietary calcium available in the food or beverage product as compared tothe calcium species provided by the present invention.

In one embodiment, a calcium source and citric acid reactants arecombined at room temperature (i.e., approximately 20 to 30° C.) withinthe above-prescribed mole proportions in an aqueous environment. Quicklyafter combining the calcium source and citric acid reactants, theresulting reaction mixture is dried (preferably using a rapid dryingtechniques) before a sediment or haze comprising crystalline calciumcitrate can form and appear in the reaction mixture. The drying mustoccur shortly after the reaction mixture containing the calcium citratereaction product is formed in order to prevent transformation of theamorphous calcium citrate product into less stable, water-insolublecrystalline forms of the salt. How quickly the drying should take placedepends, at least in part, on the temperature. Generally and underrefrigeration conditions, such rapid drying should be carried out withinabout 30 minutes, and preferably within about 15 minutes, of thereaction mixture formation. Generally and under ambient conditions, suchrapid drying should be carried out within about 5 minutes, andpreferably within about 2 minutes, of the reaction mixture formation.Alternatively, the reaction mixture can be quickly frozen (generallywithin about 5 minutes, preferably within about 2 minutes, and morepreferably with about 1 minute of the reaction mixture formation) forlater drying; once frozen, the reaction mixture should be dried underconditions which prevent or minimize thawing. In one embodiment, a rapiddrying procedure comprising freeze drying or spray drying is used. Wherefreeze drying is used, the frozen solid piece or pieces obtained arecomminuted into a powder form after freeze drying. Where spray drying isused, the calcium and citric acid reactants preferably are chilled atthe time of their admixture and up until drying.

The calcium source or calcium-containing reactant is a calcium compoundthat reacts with citric acid in aqueous solution to form calciumcitrate. These calcium compounds include calcium oxide, calciumhydroxide, calcium carbonate, or combinations thereof. Calcium hydroxideis preferred. The calcium source can be pre-slurried in water or addeddry to the aqueous medium. Once the calcium compound and citric acidreactants are conveniently admixed in water, the reaction proceedsrapidly. The addition order of the reactants and aqueous concentrationsthereof are not particularly limited as long as adequate stirring oragitation is provided to intermix the reactants within a short period oftime; of course, the relative amounts of the calcium source and citricacid are controlled to obtain the desired mole ratio of calcium andcitrate.

The above-identified subscript values “n,” “(6n-2),” and “2” in theformulas for the amorphous calcium citrate of this invention can beobtained by controlling the relative amounts of the calcium-containingreactant and citric acid reactants used in making the amorphous salt.Temperature, reactant concentrations, agitation, or hold time beforecommencing drying or freezing are parameters in determining the physicalcharacteristics of the final product. They are controlled in mannersdescribed herein to ensure that an amorphous calcium citrate can beobtained.

The reaction between the calcium source and citric acid is exothermic innature. Therefore, preferably the reaction mixture is held in a reactionvessel or container that can be cooled by any conventional or convenientmeans for that purpose during the reaction and until dried. Generally itis preferred that the temperature be kept below about 30° C., preferablybelow about 10° C., and more preferably between about 0 and 5° C. duringthe reaction period.

To dry the reaction mixture, drying (preferably using a rapid dryingtechnique) can be performed immediately, or the reaction mixture can beimmediately frozen for later drying (preferably freeze drying). Ineither instance, the amorphous character of the calcium citrate productin the reaction mixture is preserved upon drying. The preferred methodfor drying is freeze drying. Using freeze drying, the reaction mixture,whether prefrozen or not, is placed into a conventional freeze dryer,and then dried, thereby obtaining the amorphous calcium citrate in solidform. The freeze dried solid calcium citrate product of this inventionis preferably comminuted into powder form. Namely, the relatively largefreeze dried solid(s) are pulverized into a flowable particulate suitedfor the calcium fortification applications for liquids and other foodscontemplated in embodiments of this invention. For example, theamorphous calcium citrate salt product obtained by freeze drying can beground or milled such that about 95 percent pass through a U.S. 100 mesh(about 150 micron) screen. Preferably, fine dusts are avoided since theycan pose handling problems and are generally unnecessary for achievingrapid dissolution in aqueous solutions of the amorphous salt particlesproduced according to embodiments of this invention.

Alternatively, spray drying can be used to dry the amorphous calciumcitrate of this invention. For spray drying, the calcium-containingreactant and citric acid are preferably pre-chilled before or duringadmixture (generally to below about 10° C. and preferably about 0 toabout 5° C.), and the resulting chilled mixture is quickly spray driedbefore a sediment or haze comprising crystalline calcium citrate formsand appears in the reaction mixture. The calcium-containing reactant andcitric acid again are added in the calcium:citrate mole ratio of lessthan about 2.5:2. Spray drying should be commenced soon after thecompletion of the calcium citrate producing reaction (generally withinabout 30 minutes or less) to minimize the chance of the reaction producttransforming into a less water-soluble crystalline forms of calciumcitrate, such as TCC and the like. Generally, the reaction mixture isspray dried at an inlet temperature of from about 400 to about 475° C.to deliver a dried free-flowing white powder.

The opportunities for undesirable crystalline calcium citrates to occurare primarily a function of the reaction mixture temperature, reactantconcentrations, and hold or storage time parameters. Generally, the riskof crystallization of the reaction product increases with increasingreaction mixture concentrations, temperatures, and/or hold times beforecommencing the drying procedure. The limits on these parameters can beascertained empirically in a straightforward manner for a given reactionsystem. In any event, the reaction mixture conditions should bemonitored and adjusted to avoid occurrence of water-insolublecrystalline calcium citrates in the reaction product. The presence ofwater-insoluble crystalline calcium citrates will be visually noticeableas the reaction mixture will have a slurried constitution in which solidcalcium citrate crystalline particles are suspended in the fluid.

The dry powdered amorphous water-soluble calcium citrate salts obtainedby the above-described techniques generally contain less than about 5percent water, and more typically less than about 2 percent water. Theamount of water present does not interfere with the loose, freelyflowable properties of the material. Calcium citrate products made bymethods described herein are generally free of large clumps; ifnecessary, however, large lumps can be removed using grinding or sievingtechniques. The present new salts are slightly to moderately acidic,have a low moisture content, and do not undergo any significant gain orloss of water during storage. The unique amorphous water-soluble calciumcitrate salt products of this invention also generally have a bulkdensity of about 0.1 to about 0.7 g/cc, with about 95 percent passingthrough U.S. 100 mesh (or 150 microns), and are freely-flowable, whiteto yellow-white powders. In one embodiment, an approximately 1 percentcalcium citrate salt in deionized water solution at approximately 25° C.has a pH value from about 3 to about 5, and preferably from about 3.5 toabout 4.5.

In the practice of the present invention, the amorphous water-solublecalcium citrate, and, if desired, other solutes and additives are addedto an aqueous medium in preparing a nutritional drink or beverage; thelevel of the amorphous calcium citrate and other additives should beless than their respective solubility limits, so that no sediment orsolid residue is deposited or suspended in the composition. Theamorphous water-soluble calcium citrate salts having the mole ratioprescribed herein generally can be wholly dissolved in liquidcompositions at robust calcium fortification levels without impartingundesirable taste, mouthfeel, visual appearance, or odor in the drink orbeverage. Chalky or gritty solutions containing a noticeable haze orsedimentation of the calcium citrate or other solutes are avoided.Instead, clear and smooth calcium-fortified drinks and beverages can beprovided in the present invention.

The amorphous water-soluble calcium citrate generally is added to liquidcompositions, such as RTD beverages and reconstituted powdered drinks,on an elemental calcium weight basis, at a rate of about 3 mg or more,particularly from about 3 mg to about 250 mg, more particularly fromabout 12.5 mg to about 125 mg, per fluid ounce of the beverage. An eightounce serving of a calcium-fortified beverage prepared according to theinvention delivers approximately 2 to approximately 200 percent of theDV for calcium (about 1000 mg/day). The amount of amorphous calciumcitrate added to solution to achieve the above-indicated calciumaddition levels can be readily calculated and implemented. In the caseof the reconstituted form made by dissolving a powdered mix in liquid,formulation instructions can be provided on the packaging for consumersto guide them on how to implicitly or explicitly formulate this calciumconcentration. Using these introduction levels of the calcium, asobtained from amorphous calcium citrate, a typical eight fluid ounceserving can provide a rich source of an individual's DV for calcium.

For either RTD or reconstituted powdered beverages according to thepresent invention, the primary ingredient will be the amorphouswater-soluble calcium citrate alone or in combination with a flavoringmaterial, and a liquid in which the calcium citrate and, if present, theflavoring ingredient, are soluble. Other soluble and edible ingredientscan be added as desired so long as they do not adversely affect theorganoleptic properties.

The liquid in which the calcium citrate and flavoring material, and anyother ingredients, is dissolved is preferably water based. Watercontaining a relatively small amount (generally less than about 20percent) of alcohol can also be used in appropriate products.Water-based liquid vehicles are preferred in the practice of theinvention. The proportion of liquid generally will be that sufficient topermit solubilization of the ingredients and also sufficient to permitthe desired strength/dilution of the flavoring agents to be achieved.Generally, the proportion of water used in fruit drink beveragesencompassed by the invention, whether RTD or reconstituted forms, willbe about 50 to about 99 percent.

For fortified fruit-flavored beverages, water-soluble andwater-dispersible flavoring agents can be used, including commerciallyavailable flavoring agents for fruit drinks. Common fruit flavoringmaterials useful in this invention include, for example, orange oil,lime oil, lemon oil, and so forth. Other flavoring materials also can befound in published formulation recipes for fruit drinks. Also, naturalfruit juice concentrates can be added to the beverages to provide oraccentuate the fruit flavoring desired. These concentrates typicallywill be in liquid, pulped, or syrup forms. A fruit juice “concentrate”generally contains at least about 45 percent fruit juice. In anotherembodiment, a flavoring agent is contained in the beverage which impartsa grapefruit, kiwi, raspberry, cherry or other fruit flavor.

Food colorings also can be added to the inventive beverages, such asU.S. Certified Food Colors. Preservatives also can be added to theinventive beverages, such as sodium benzoate, ascorbic acid, propyleneglycol, and the like. Also, in the case of the dry powdered beveragemixes of the invention, users often can be expected to use tap water toreconstitute the beverage. In that tap water often is slightly alkalinedue to the presence of dissolved mineral salts therein, edible acids,such as citric acid, malic acid, and the like, also can be included toneutralize the alkalinity of tap water or for other purposes.

The beverages of this invention also can contain a sweetener. Suitablesweeteners include, for example, sucrose, glucose, fructose, hydrolyzedcorn starch, maltodextrin, corn syrup solids, lactose, high fructosecorn syrup, fructooligosaccharides, artificial sweeteners, and the likeas well as mixtures thereof. Suitable artificial sweeteners include, forexample, aspartame, sucralose, saccharine, cyclamates, acesulfamepotassium, and the like as well as mixtures thereof. In the case ofpowdered dry mixes, the sweetener generally will be present ingranulated form in the mix prior to reconstituting the drink. The amountof sweetener can vary, but generally, if present, is in the range offrom about 5 to about 25 percent of the RTD or reconstituted beverage.

In that embodiments of the invention encompass nonfat beverage products,the desirable mouthfeel that would normally be provided by fat contentcan instead be provided, at least to some extent, by non-fatstabilizers, including celluloses (e.g., carboxymethyl cellulose, sodiumcarboxymethyl cellulose, hydroxymethyl cellulose, hydroxypropyl methylcellulose, cellulose gel) and/or xanthan gum, guar gum, gum arabic, andso forth. In reconstituted powdered beverage mixes of the invention, theamount of such stabilizers generally can be from about 0.1 to about 15percent.

Fat also optionally can be introduced as an ingredient of the beverages.Suitable fats include, for example, soy oil, hydrogenated soy oil,fractionated coconut oil, high oleic safflower oil, corn oil, canolaoil, and the like as well as mixtures thereof. For example, soy drinkscan be prepared as RTD beverages or as beverages reconstituted frompowdered dry mixes according to embodiments of the invention.

The powdered beverage mixes of the present invention are formed from adried flavor base containing the calcium citrate salts of thisinvention. The flavor base can be dried by conventional means known tothe art, such as spray drying, evaporative drying, vacuum drying, orfreeze drying. Preferably, the drying method provides rapidlydissolvable particles. Sugar, and/or stabilizers such as cellulose andthe like, also can be used as carriers for other ingredients of thedried flavor base. Additional optional ingredients include one or moreof other common ingredients for beverages (e.g., functional agents likeflow agents such as silica, or caffeine, and so forth). For healthdrinks, a vitamin/mineral premix also could be included.

Powdered beverage mixes include fruit flavored powdered drinks and soy“milk” beverages. RTD beverages include fruit flavored drinks and soy“milk” drinks. The beverages fortified according to this invention alsocan be frozen.

A soluble, dry powdered beverage mixture according to one illustrative,non-limiting, embodiment of the invention, comprises, on a dry weightbasis: about 5 to about 50 percent amorphous water-soluble calciumcitrate and about 0.1 to about 20 percent flavoring agent. In oneembodiment, when reconstituted from a powdered mix, or as prepareddirectly as an RTD, the liquid composition provided contains the calciumcitrate in an amount, based on calcium content, providing at least about1 percent of the DV for calcium per fluid ounce of the liquidcomposition; a flavoring concentrate in an amount of about 0.02 to about20 percent; and water in an amount of about 50 to about 95 percent. Inthe instance of powdered beverage mixes, instructions can be provided onthe product container which instruct a consumer how to formulate aliquid composition that contains these ingredients in such proportions.The ingredients of the inventive beverage compositions are mixed withthe liquid vehicle with stirring and agitation to the extent needed todissolve the ingredients and ensure a substantially uniform dispersionof the ingredients is achieved in the liquid carrier or vehicle.

As discussed above, the beverages that can be fortified according tothis invention include powdered beverage mixes and ready-to-drink (RTD)beverages. Whether prepared as a RTD or reconstituted beverage, it hasbeen observed and demonstrated that the calcium citrate used infortifying beverages according to embodiments of this invention iswholly dissolved and nutritionally available.

The Examples that follow are intended to illustrate, and not to limit,the invention. All percentages used herein are by weight and the ratiosof calcium to citrate are expressed as mole ratios, unless otherwiseindicated.

EXAMPLES Example 1

A series of calcium citrate salts was produced according to theembodiments of the invention for the purpose of identifying a practicalupper limit of calcium:citrate mole ratio that can be easily produced inamorphous form while preventing significant solidification,crystallization, or sedimentation of the reaction mixture prior todrying. Powders having calcium:citrate mole ratios of 1:2 (monocalciumcitrate or MCC), 1.5:2 (sesqui-calcium citrate or SCC), 2:2 (dicalciumcitrate or DCC), 2.25:2, 2.4:2, 2.5:2, and 3:2 (tricalcium citrate orTCC), respectively, were separately produced by quickly pouring roomtemperature (about 22° C.) calcium hydroxide suspensions (7.4 to 22.2 gin 100 g water) into room temperature citric acid solutions (38.4 g in100 g water), stirring vigorously for several seconds or until thehydroxide completely dissolved to form clear yellow-green solutions,quickly pouring the solutions into trays, immediately freezing viadirect addition of liquid nitrogen to prevent formation of insoluble TCCor any other solid material, then freeze drying to obtain white granulesthat were easily comminuted to fine powders. The higher thecalcium:citrate mole ratio used and the higher the reactantconcentration, the faster the initially clear calcium citrate solutionsbegan to haze, presumably from the onset of TCC formation.

Without desiring to be limited to theory, it is thought that formationof TCC, even at low calcium:citrate ratios, can occur viathermodynamically favorable disproportionation reactions due to the highsolubility product constant of TCC. This would explain why a wide rangeof commercial calcium citrate salts obtained for evaluation in calciumfortified beverages all contained significant amounts of insolublematter, presumably TCC, and immediately formed an unsightly precipitatein water.

All solutions formulated with a calcium:citrate mole ratio up to 2.25:2were prepared and frozen without visible haze or sediment formation whentreated in the manner described. However, solutions that were allowed tostand for longer than about 30 minutes produced large amounts ofsediment (i.e., crystalline material). The 2.5:2 mole ratio solution,prior to freezing, seemed to produce a small amount of TCC in the formof suspended haze, despite rapid handling. The 3:2 mole ratio solutionbegan to precipitate crystalline TCC very rapidly, seemingly even beforeall of the calcium hydroxide dissolved, making production of asediment-free amorphous powder virtually impossible using the presentmanufacturing techniques. Although these experiments were performedusing calcium hydroxide as the calcium source, calcium oxide and calciumcarbonate also can be used as the calcium source.

The 2:2 mole ratio calcium citrate powder was examined using lightmicroscopy to confirm the presence of a non-crystalline, amorphousstructure. Micrographs were obtained to demonstrate the structuraldifferences between this amorphous 2:2 mole ratio calcium citrate powderand a conventional crystalline TCC reference product (TCC tetrahydratemanufactured by Fortitech Inc.). The two materials had very differentstructural features when viewed under magnification with normal light.The two materials were then observed using polarized light. Thecommercial TCC exhibited essentially complete birefringence, therebyconfirming a crystalline structure containing (at most) an insignificantamount of amorphous matter. The 2:2 mole ratio calcium citrate powderexhibited virtually zero birefringence under polarized light, therebyconfirming an amorphous structure containing (at most) an insignificantamount of crystalline matter (i.e., less than one percent).

Addition of 240 ml room temperature water to 2 g of the 2:2 mole ratiocalcium citrate powder (bulk density of about 0.18 g/cc) produced aninstantly dissolving clear solution, providing 350 mg calcium per eightfluid ounce serving. The solution remained completely free of haze andsediment for at least two days of storage at room temperature. Similaror even better results were obtained from the salts prepared havingcalcium:citrate mole ratios lower than 2:2, even when dissolved in waterat higher concentrations.

The 2.25:2 and 2.4:2 mole ratio calcium citrate powders dissolvedcompletely in water (at levels sufficient to provide 350 mg calcium pereight fluid ounce serving) to form clear solutions that were free ofsediment for at least six hours. These solutions, however, produced avery small amount of fine sediment overnight (i.e., just visible). Thesepowders, in spite of the sediment produced, would provide veryacceptable performance in many, if not most, food applications,including instant beverage mixes and acidified RTD beverages.

The 2.5:2 mole ratio calcium citrate powder (in an amount sufficient toprovide 350 mg calcium per eight fluid ounce serving) dispersedcompletely in water, but a small undissolved portion formed a faintmilky haze that began to slowly produce fine sediment after severalminutes. This behavior might also be acceptable in some situations(i.e., opaque instant beverage mixes), but appears to represent apractical upper limit for applications that require high levels ofsoluble calcium and/or require a sediment-free transparent appearance.

The 3:2 mole ratio calcium citrate powder (added at levels sufficient toprovide 350 mg calcium per eight fluid ounce serving) did not completelydisperse in water; it formed a hazy suspension along with a small amountof fine sediment that gradually increased over time. Both the 2.5:2 and3:2 mole ratio calcium citrate solutions produced very large amounts offluffy white sediment when allowed to stand overnight at roomtemperature. By comparison, the crystalline commercial 3:2 mole ratioTCC reference material (bulk density of 0.45 g/cc) did not completelydisperse in water under the same conditions and immediately produced alarge amount of a coarse, gritty white sediment. Even a crystallinecommercial 1:2 mole ratio MCC product (calcium citrate monohydratemanufactured by Dr. Paul Lohmann GMBH, Germany) did not completelydisperse in water in an attempt to produce a 350 mg calcium per eightounce serving size. It immediately produced a large amount of coarse,gritty white sediment that took several days to completely dissolve atroom temperature.

Powders prepared according to the present invention, as described above,were added to water at a level of 1 percent to measure pH and assessinitial solution appearance. The crystalline commercial 3:2 mole ratioTCC reference material was included for comparison. Results are providedin the following table: Calcium:Citrate Calcium Initial Solution MoleRatio Content (%) Solution pH Appearance 1:2 9.5 3.4 No haze; nosediment 1.5:2   13.6 3.8 No haze; no sediment 2:2 17.4 4.1 No haze; nosediment 2.25:2   19.2 4.3 No haze; no sediment 2.4:2   20.2 4.4 Nohaze; no sediment 2.5:2   20.9 4.5 Slight haze; some sediment (fine) 3:224.1 5.4 Moderate haze; more sediment (fine)  3:2* 21.1 5.9 Milky haze;most sediment (coarse)*Crystalline commercial 3:2 mole ratio TCC reference material

In summary, the goal of creating amorphous calcium citrate salts thatcan be instantly and completely dissolved in water without production ofhaze or sediment and which can provide substantial amounts of calciumwas achieved with calcium:citrate mole ratio below 2.5:2.

Example 2

As an alternative to freeze drying, an amorphous 2:2 mole ratio calciumcitrate salt, using the same ingredients as in Example 1, was alsosuccessfully produced via spray drying (i.e., pilot scale drying usingstandard operating conditions and procedures). In this case, chilledcalcium hydroxide and citric acid solutions were combined and rapidlyspray dried before solidification or sediment formation could occur.Addition of 240 ml room temperature water to 2 g of this fine whitepowder produced an instantly dissolving clear solution, providing 350 mgcalcium per eight ounce serving, that remained completely free ofsediment for at least three days at room temperature. In a large scalecommercial process, the citric acid and calcium hydroxide (or othersuitable reagents) would be beneficially combined just prior to spraydrying to limit the potential for solidification or sediment formation.

Based on the successful production of an amorphous 2:2 mole ratiocalcium citrate salt on a pilot plant scale, the same general procedurewas scaled up using a larger spray dryer. Several identical batches ofcitric acid solution and slurried calcium hydroxide suspension wereprepared using the following procedure. Citric acid (1 kg) was dissolvedin 2.6 liters water. Calcium hydroxide (385.5 g) was separately slurriedin 2.6 liters water. All batches were chilled to a temperature of 4° C.using refrigeration.

One batch of the chilled citric acid solution was poured into a mix tankjacketed with cooling water and one batch of calcium hydroxidesuspension was added with stirring. In less than one minute, the mixturecleared to form a yellowish solution and the temperature increased to 9°C., indicating that chemical reaction to form 2:2 mole ratio calciumcitrate had occurred. The clear solution was immediately pumped into asemi-works scale spray dryer, fitted with an atomizing nozzle, at a flowrate of about 0.5 kg per minute. Additional batches of citric acidsolution and calcium hydroxide suspension were similarly added to themix tank as needed to prevent complete emptying. A sample of fine whitepowder was collected from the spray dryer after ten minutes ofoperation. The powder had an amorphous structure and rapidly dissolvedin cold water without haze or precipitate to provide a solution having350 mg calcium per eight fluid ounces. After a further fifteen minutes,the cooling water was shut off from the jacketed mix tank. A sample ofpowder collected from the spray dryer after thirty minutes did notdissolve completely in water due to the presence of a significant amountof crystalline calcium citrate. In less than one hour, the atomizingnozzle and pipe between the mix tank and the spray dryer became pluggedwith an accumulated deposit of insoluble crystalline calcium citrate.This example demonstrates the benefit of maintaining calcium citratesolutions at low temperature when spray drying and the necessity ofrapidly drying to prevent detrimental solidification and precipitationduring processing.

Example 3

This Example illustrates the preparation of an amorphous salt havingcalcium:citrate mole ratio of 1:2 and which contains nutritive levels ofiron, potassium, and calcium. Iron sulfate heptahydrate (0.54 g),potassium hydroxide (10.20 g), and citric acid (18.46 g) weresequentially dissolved in 100 g water. Calcium hydroxide 3.70 g wasslurried in 100 g water and poured into the solution containing citricacid at room temperature (about 22° C. The resulting solution had alight yellow color and was clear and sediment free. The solution waspoured into a tray, rapidly frozen by direct addition of liquidnitrogen, and then freeze dried.

The dried granular salt had a light yellow color and was easily groundto a fine powder using mortar and pestle. The powder (1.4 g) dissolvedinstantly and completely in eight fluid ounces of cold water to providea liquid composition containing FDA good-source levels of iron (about 5mg), calcium (about 100 mg), and potassium (about 350 mg). This solutionhad a pH of 5.7 and an appealing light yellow appearance and remainedfree of haze and sediment for at least eight hours. Addition of 5 ggranular sugar to the solution produced a nutritive beverage havingpleasant citrus-like flavor and appearance.

Example 4

The freeze-dried 2:2 mole ratio amorphous calcium citrate salt ofExample 1 was used to impart a FDA excellent-source level of calcium totwo commercial instant beverage mixes. One sample of the amorphous salt(2.0 g) was combined with 17.0 g sweetened Cherry Kool-Aid® powderedinstant drink mix in a 400 ml beaker. The powdered drink mix containedsugar, fructose, citric acid, calcium phosphate (not a significantsource of calcium), artificial flavor, artificial colors, and ascorbicacid. Another sample of the amorphous salt (2.0 g) was combined with 2.0g artificially-sweetened Lemon CRYSTAL LIGHT® powdered instant drink mixand placed in a 400 ml beaker. The powdered drink mix contained citricacid, potassium citrate, maltodextrin, aspartame, magnesium oxide,natural flavor, lemon juice solids, acesulfame potassium, artificialcolors, and BHA.

Each of the calcium-fortified powdered mixtures were combined with eightfluid ounces of cold water to produce a beverage having excellent flavorand appearance. In both cases, the amorphous calcium citrate saltdissolved immediately, without the need for stirring, when water wasadded to each of these calcium-fortified powdered drink mixes. Eachreconstituted beverage provided 350 mg calcium per serving and remainedfree of sediment for at least 24 hours.

For comparison purposes only, similar beverages were prepared bysubstituting 1.7 g of the crystalline TCC reference product in place ofthe amorphous salt in each of these powdered drink mixes. In each case,large amounts of coarse gritty sediment were formed immediately; thesediment completely covered the bottom of the beakers to a depth ofabout a millimeter. The sediments did not dissolve with rapid stirringor with the passage of time. The crystalline calcium citrate saltcombined with these powdered drink mixes did not provide effectivecalcium fortification; the beverages had unacceptable appearance andoverall quality.

Example 5

Fortified RTD beverages were formulated with several forms of calciumcitrate. The visual appearance, flavor, and stability of the productswere evaluated over a seven-month period by an experienced panel.Identical samples of each fortified beverage were prepared for shelflife testing under both ambient (22° C.) and refrigerated (4° C.)storage conditions.

The freeze dried amorphous 2:2 mole ratio calcium citrate salt (17%calcium) of Example 1 was successfully used to fortify a ready-to-drinksugar-free lemon-flavored beverage (CRYSTAL LIGHT®) with 350 mg calciumper eight fluid ounce serving (“excellent source of calcium” level). Toformulate the calcium-fortified powdered mix, eight fluid ounces ofcommercial CRYSTAL LIGHT® RTD beverage mix was mixed thoroughly with 2 gof the freeze dried amorphous 2:2 mole ratio calcium citrate salt. Thecalcium-fortified beverage remained sediment free and exhibitedacceptable flavor and appearance throughout the seven-month shelf lifeevaluation period at both room temperature and under refrigerationconditions.

However, when crystalline commercial MCC monohydrate (9 percent calcium)and crystalline TCC tetrahydrate (21 percent calcium) salts were used inplace of the amorphous 2:2 mole ratio calcium citrate salt (in amountsdesigned to provide the same level of calcium), the resulting beveragesotherwise formulated in the same manner were unacceptable due tonoticeable sediment formation upon admixture of the ingredients.

The same freeze dried amorphous 2:2 mole ratio calcium citrate salt ofExample 1 was used to similarly fortify a ready-to-drink thermallyprocessed sweetened orange-flavored beverage (TANG®). To formulate thecalcium-fortified beverage, eight fluid ounces of a commercial TANG®beverage was mixed thoroughly with 2 g of the freeze dried amorphous 2:2mole ratio calcium citrate salt. The resulting calcium-fortifiedbeverage was exposed a high temperature short time (HTST) sterilizationprocedure prior to bottling. The calcium fortifying agent remained insolution throughout the thermal processing operation without anyapparent loss of solubility or sediment formation.

While the invention has been particularly described with specificreference to particular process and product embodiments, it will beappreciated that various alterations, modifications and adaptations maybe based on the present disclosure, and are intended to be within thespirit and scope of the present invention as defined by the followingclaims.

1. An amorphous water-soluble calcium citrate salt having a mole ratioof calcium to citrate in the range of from about 1:2 to less than 2.5:2,wherein the calcium citrate salt is amorphous and water soluble andwherein the amorphous water-soluble calcium citrate salt, when dissolvedin water to provide about 10 mg calcium per fluid ounce, does not form avisible haze or sediment for at least about 2 days at ambienttemperatures.
 2. The amorphous water-soluble calcium citrate saltaccording to claim 1, wherein the mole ratio of calcium to citrate isless than about 2.25:2.
 3. The amorphous water-soluble calcium citratesalt according to claim 2, wherein the calcium citrate comprises a saltrepresented by the formulaCa_(n)(H)_((6-2n))(C₆H₅O₇)₂ where n is less than about 2.25.
 4. Acalcium-fortified liquid composition comprising calcium citrate having amole ratio of calcium to citrate in the range of from about 1:2 to lessthan 2.5:2 and a potable liquid in an amount effective to dissolve thecalcium citrate, wherein the calcium citrate salt is amorphous and watersoluble and wherein the calcium citrate salt, when dissolved in thepotable liquid to provide about 10 mg calcium per fluid ounce, does notform a visible haze or sediment for at least about 2 days at ambienttemperatures.
 5. The calcium-fortified liquid composition according toclaim 4, wherein the mole ratio of calcium to citrate is less than about2.25:2.
 6. The calcium-fortified liquid composition according to claim4, wherein the amorphous calcium citrate is present in an amountproviding at least about 3 mg calcium per fluid ounce of thecalcium-fortified liquid composition.
 7. The calcium-fortified liquidcomposition according to claim 5, wherein the amorphous calcium citrateis present in an amount providing at least about 3 mg calcium per fluidounce of the calcium-fortified liquid composition.
 8. Thecalcium-fortified liquid composition according to claim 4, wherein theamorphous calcium citrate is present in an amount providing about 6 mgto about 250 mg calcium per fluid ounce of the calcium-fortified liquidcomposition.
 9. The calcium-fortified liquid composition according toclaim 5, wherein the amorphous calcium citrate is present in an amountproviding about 6 mg to about 250 mg calcium per fluid ounce of thecalcium-fortified liquid composition.
 10. The calcium-fortified liquidcomposition according to claim 4, wherein the liquid composition is ahealth drink, a flavored beverage, or a pharmaceutical liquidcomposition.
 11. The calcium-fortified liquid composition according toclaim 5, wherein the liquid composition is a health drink, a flavoredbeverage, or a pharmaceutical liquid composition.
 12. Thecalcium-fortified liquid composition according to claim 4, furthercomprising a flavoring agent.
 13. The calcium-fortified liquidcomposition according to claim 12, wherein the flavoring agent comprisesa fruit juice concentrate, a flavor concentrate, a sweetener, orcombinations thereof.
 14. The calcium-fortified liquid compositionaccording to claim 4, wherein the potable liquid comprises water. 15.The calcium-fortified liquid composition according to claim 4, theamorphous calcium citrate is present in an amount to provide at leastabout 1 percent of the U.S. Daily Value for calcium per eight fluidounce serving of the calcium-fortified liquid composition; wherein thecalcium-fortified liquid composition further comprises a flavoringconcentrate in an amount of about 0.02 to about 20 percent; and whereinthe potable liquid comprises water which is present in an amount ofabout 50 to about 95 percent.
 16. A soluble powdered beverage mixturewhich can be reconstituted in a potable liquid to form acalcium-fortified beverage, said mixture comprising an amorphouswater-soluble calcium citrate having a mole ratio of calcium to citratein the range of from about 1:2 to less than 2.5:2 and a flavoring agent,wherein the calcium citrate salt is amorphous and water soluble andwherein the calcium citrate salt, when dissolved in the potable liquidto provide about 10 mg calcium per fluid ounce, does not form a visiblehaze or sediment for at least about 2 days at ambient temperatures. 17.The soluble powdered beverage mixture according to claim 16, wherein themole ratio of calcium to citrate is less than about 2.25:2.
 18. Thesoluble powdered beverage mixture according to claim 16, wherein theamorphous calcium citrate is present in an amount to providing at leastabout 3 mg calcium per fluid ounce of the calcium-fortified beverage.19. The soluble powdered beverage mixture according to claim 17, whereinthe amorphous calcium citrate is present in an amount providing at leastabout 3 mg calcium per fluid ounce of the calcium-fortified liquidcomposition.
 20. The soluble powdered beverage mixture according toclaim 16, wherein the amorphous calcium citrate is present in an amountproviding about 6 mg to about 250 mg calcium per fluid ounce of thecalcium-fortified liquid composition.
 21. The soluble powdered beveragemixture according to claim 17, wherein the amorphous calcium citrate ispresent in an amount providing about 6 mg to about 250 mg calcium perfluid ounce of the calcium-fortified liquid composition.
 22. A methodfor producing an amorphous water-soluble calcium citrate salt,comprising forming a reaction mixture by reacting a calcium compoundwith citric acid in an aqueous solution at a temperature of less thanabout 60° C. to form a calcium citrate reaction product which has a moleratio of calcium to citrate in the range of from about 1:2 to less than2.5:2, and drying the reaction mixture effective to provide theamorphous water-soluble calcium citrate salt in solid form, wherein theamorphous water-soluble calcium citrate salt, when dissolved in water toprovide to about 10 mg calcium per fluid ounce, does not form a visiblehaze or sediment for at least about 2 days at ambient temperatures. 23.The method of claim 22, wherein the drying is performed before thereaction mixture stands for a period of time at which a water-insolublecalcium citrate salt forms in the reaction mixture.
 24. The method ofclaim 22, wherein the calcium compound is selected from the groupconsisting of calcium oxide, calcium hydroxide, calcium carbonate, andcombinations thereof.
 25. The method of claim 22, wherein the dryingcomprises freeze drying the reaction mixture.
 26. The method of claim25, further comprising comminuting the freeze-dried calcium citrate saltinto powder form.
 27. The method of claim 22, wherein the dryingcomprises spray drying the reaction mixture.
 28. The method of claim 22,wherein providing the reaction mixture further comprises chilling amixture of an aqueous slurry of the calcium compound and aqueoussolution of the citric acid to a temperature below about 10° C., andspray drying the reaction mixture at the chilled temperature.
 29. Themethod of claim 22, wherein the mole ratio of calcium to citrate is lessthan about 2.25:2.
 30. A method for increasing the dietary calciumintake in a mammal by administering a beverage fortified with anamorphous water soluble calcium citrate to the mammal in an effectiveamount, wherein the amorphous water soluble calcium citrate has acalcium:citrate mole ratio in the range of from about 1:2 to less than2.5:2, and wherein the amorphous water soluble calcium citrate salt,when dissolved in water to provide about 10 mg calcium per fluid ounce,does not form a visible haze or sediment for at least about 2 days atambient temperatures.
 31. The method according to claim 30, wherein themammal is a human.
 32. The method according to claim 31, wherein themole ratio of calcium to citrate is less than about 2.25:2.